1. The Field of the Invention
This invention relates in general to equipment used in the process of blending soils, sludges and liquid/solid mixtures with dry powdered and liquid chemicals. In particular, this invention relates to blending equipment used in the environmental field to stabilize contaminated soils, sludges and liquid/solid mixtures so the resulting product will be rendered harmless to the environment.
2. The Prior Art
Due to the nature of the environmental soil remediation business, equipment used in the field have been adaptations of construction or excavation equipment. An early form of blending stabilizing chemicals into soil involved spreading the chemicals over the soil and turning it in with a back hoe. Other attempts have involved turning a large auger vertically into the soil while injecting chemicals at or through it. U.S. Pat. No. 5,013,185 dated May 7, 1991 involved using multi-shafted augers to inject and blend stabilization chemicals into soils. These in situ methods however do not ensure accurate or thorough mixing of the materials or allow for testing of composition during or after the operation.
Other equipment used involves adaptation of concrete mixing equipment, either rotary barrel or volumetric mixers. Neither type will adequately process either clay-like or sludge consistencies and ensure proper mixing. U.S. Pat. No. 4,913,586 dated Apr. 3, 1990 describes a process for blending soil but makes no provisions for a liquid additive necessary for complete chemical stabilization of soils. It is also limited in previously excavated situations and where tank removals occur.
From the foregoing, it will be appreciated that what is needed in the art is equipment capable of accurately metering soils or sludges of any consistency from dry to nearly liquid. It would be a further advancement in the art for the equipment to blend all materials accurately and completely on a continual production basis allowing high volume throughout.